牛蒡子苷元抑制TLR4/TRAF6/NF-κB信号通路对哮喘模型大鼠气道重塑和Th1/Th2免疫平衡的影响

Effects of arctigenin on airway remodeling and Th1/Th2 immune balance in asthma model rats by inhibiting TLR4/TRAF6/NF-κB signaling pathway

目的研究牛蒡子苷元抑制Toll样受体4(TLR4)/肿瘤坏死因子受体相关因子-6(TRAF6)/核转录因子-κB(NF-κB)信号通路对哮喘模型大鼠气道重塑和Th1/Th2免疫平衡的影响。方法构建急性哮喘大鼠模型,随机分为5组(每组12只模型大鼠):模型组、牛蒡子苷元低、高剂量组、脂多糖(LPS,TLR4激活剂)组、牛蒡子苷元+LPS组,以12只Wistar正常大鼠作为对照组。分组处理后,观察各组大鼠哮喘症状并做评分、分类计数各组大鼠支气管肺泡灌洗液(BALF)中炎症细胞、检测各组大鼠肺组织病理变化、血清IgE水平、BALF和血清中白细胞介素(IL)-4、干扰素γ(IFN-γ)水平、IFN-γ/IL-4及肺组织TLR4/TRAF6/NF-κB通路相关蛋白表达。结果与对照组相比,模型组大鼠肺组织产生严重病理损伤,哮喘症状评分、WAt/Pbm、WAm/Pbm、BALF中巨噬细胞及淋巴细胞计数、血清IgE水平、BALF与血清中IL-4水平、肺组织TLR4、TRAF6表达及p-NF-κB p65/NF-κB p65升高(P<0.05),BALF与血清中Th1型细胞因子IFN-γ水平、IFN-γ/IL-4降低(P<0.05);与模型组相比,各牛蒡子苷元处理组中模型鼠的上述改变均被扭转,且高剂量牛蒡子苷元作用更强;LPS组大鼠各指标变化与牛蒡子苷元处理组相反,另外LPS可逆转高剂量牛蒡子苷元对大鼠各指标的作用。结论牛蒡子苷元可通过抑制TLR4/TRAF6/NF-κB信号激活而阻止哮喘大鼠气道炎症,促使Th1/Th2免疫平衡向Th1转移,改善大鼠气道重塑和肺损伤。

This study was designed to evaluate the influences of arctigenin on airway remodeling and Th1/Th2immune balance in asthma model rats by inhibiting Toll-like receptor 4(TLR4)/tumor necrosis factor receptorrelated factor-6(TRAF6)/nuclear transcription factor-κB(NF-κB)signaling pathway.Rat models of acute asthma were established by sensitization and challenge with egg protein and aluminum hydroxide suspension.Model rats were randomly grouped into 5 groups(12 model rats in each group):model group,arctigenin low-dose group,arctigenin high-dose group,lipopolysaccharide(LPS,TLR4 activator)group and arctigenin+LPS group,with 12Wistar normal rats as control group treated with equal dose of normal saline.After the rats were treated with arctigenin or/and LPS,the asthma symptoms of the rats in each group were observed and scored;Wright staining was used to classify and count inflammatory cells in bronchoalveolar lavage fluid(BALF)of rats in each group;HE staining was used to detect the pathological changes of lung tissues;microplate reader was used to detect serum IgE level,as well as the levels of interleukin(IL)-4,interferon gamma(IFN-γ)levels and IFN-γ/IL-4 in BALF and serum;and Western blot was used to detect theexpression of TLR4/TRAF6/NF-κB pathway-relatedproteins in lung tissue of rats.Compared with the control group,the model group demonstrated severe pathological damage in lung tissue,higher levels of asthma symptomscore,WAt/Pbm,WAm/Pbm,macrophage and lymphocyte counts in BALF,higher levels of serum Ig E,BALF IL-4,serum IL-4,and higher expression of TLR4,TRAF6 and p-NF-κB p65/NF-κB p65(P<0.05)in lung tissue,butlower levels of Th1 cytokine IFN-γand IFN-γ/IL-4 in BALF and serum(P<0.05).While arctigenin,especially inhigh-dose,could reverse these changes in model rats of arctigenin treatment group.But the changes of indexes inLPS group were opposite to those in arctigenin treatment group,furthermore,LPS can reverse the effect of high-dosearctigenin on various indexes of rats.Taken together,arctigenin can prevent airway inflammation in asthmatic rats byinhibiting the activation of TLR4/TRAF6/NF-κB signaling,promote the transfer of Th1/Th2 immune balance to Th1,improve airway remodeling,and alleviate lung injury in rats.